PROJECT SUMMARY/ABSTRACT Depression is the leading cause of disability worldwide, with more than 300 million people affected. Most adults with depressive symptoms make at least one annual visit to a primary care physician (PCP). As such, primary care offers a ripe opportunity to identify and treat adults with depressive symptomatology. Yet, depression has historically been undertreated in primary care, and more than two-thirds of U.S. adults who screen positive for depression do not receive treatment. Mobile health (mHealth) technologies, and specifically mobile apps, offer an ideal strategy to meet the need for evidence-based psychological treatment via primary care. Via our Phase I STTR, we developed and preliminarily clinically evaluated ?Moodivate?, a self-help mobile app depression treatment informed by the Brief Behavioral Activation (BA) Treatment for Depression. Moodivate was designed specifically to address the need for disseminable, evidence-based depression treatment via primary care. Our Phase I STTR was successful in meeting all aims, resulting in publication of both a treatment development paper and a primary outcomes paper. Specific to feasibility and acceptability, 70% of Moodivate participants recruited from primary care continued to use the app one month after download and 50% two months after download. Specific to efficacy, Moodivate (vs. treatment as usual) led to significantly greater decreases in depression over time, with treatment gains sustained over two-months of follow-up. Although these data are promising, several key issues must be resolved before Moodivate commercialization. First, although the end user and one customer for Moodivate is the patient, an additional customer is the healthcare system. Thus, Moodivate must be integrated with the healthcare system (i.e., with the Electronic Health Record (EHR)) to facilitate provider referral and monitoring of treatment response. Second, our experience shows that minor product modifications are needed prior to additional clinical testing and eventual commercialization. Third, to advance toward commercialization and collect data potentially necessary for FDA approval, a larger-scale clinical trial is needed. Fourth, any downstream commercialization of Moodivate within healthcare systems requires that we first quantify in financial terms its cost-effectiveness, both as a stand-alone app and as integrated with the EHR. Thus, the Aims of this Phase II STTR are to 1) Refine Moodivate and develop the EHR provider portal, 2) Via a three-arm randomized controlled trial (N=600), examine the efficacy of Moodivate vs. Moodivate + EHR integration vs. treatment as usual for the treatment of depressive symptoms within primary care, and 3) Conduct a cost-effectiveness analysis to quantify the financial benefits of Moodivate and Moodivate + EHR implementation within primary care. Phase II research activities are coupled with a strong commercialization plan which together will propel our company toward Phase III and will address the public health need for primary care-based depression treatment.